My Audio & Video files got Deleted

There is some sort of virus in my pc that has deleted all of my audio and video files in all my drives except for the one in which windows is installed (which is the 'C' Drive). All the other partitions in my hard disk with audio and video files got deleted. Even the files in my other 160gb hard disk which had a single partition. When i download any such file onto a partition other than 'C' then after restart they get deleted again. Nothing else seems to have been deleted. I can't access the task manager or the search function. I managed to get my task manger function back after searching through stuff online and discovered a command that would let me use it again. But again after restarting the system, i have to run it again. I ran a scan using avg and also ran an online scan through symantec, but didn't find anything except for cookies. My CPU is also running at about 50% even when it is idle. How do i get rid of this virus???

You need to boot in safe mode and scan. Try something else besides AVG like MBAM and/or GAS. Once you get rid of the virus (if that is the problem) you may be able to recover your partitions/files using some kind of recovery software. Or if possible do it on another PC. The more you write to that drive/partition where you files were the less chance you have of recovery.